Chitosan-Supported Molecularly Imprinted Polypyrrole@MoSe₂ Nanosheet-Based Bioinspired Electrochemical Sensor for Improved Quantification of Gut Microbiota-Derived Hippuric Acid

Hippuric acid (HA) is a well-known gut microbiota-derived metabolite involved in the development of various diseases such as chronic kidney disease, Chron's disease, and inflammatory bowel disease. HA being one of the most commonly found metabolites in gut microbiota is an important analyte considered for establishing an efficient, quick, sensitive, and reliable method for its detection in human samples. In this work, a molecularly imprinted polymer (MIP) technique has been focused on the electrochemical detection of HA using soft materials, as well as a bioinspired technique. Different characterization techniques have been used to validate the synthesis of MoSe₂ NS, polypyrrole (PPY)@molybdenum diselenide (MoSe₂)-MIP, such as X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, atomic force microscopy, contact angle, Brunauer-Emmett-Teller method, and transmission electron microscopy. Also, density functional theory computational study has been used to establish the theoretical interaction between the pyrrole (monomer) and HA (target analyte), as well as explore the highest occupied molecular orbital and lowest unoccupied molecular orbital interactions followed by molecular electrostatic potential and Mulliken charges. The chitosan-polypyrrole@MoSe₂-MIP showed 14.92 μA log₁₀(ng/mL)^-1 cm^-2 sensitivity and a low limit of detection of 0.76 ng/mL in the presence of the analyte using the differential pulse voltammetry technique. The fabricated sensor was also deployed to assess the level of HA in the spiked urine sample, further showing the recovery of 93-108%. Also, the green profile score for the PPY-MIP-based sensor is assessed using the Analytical GREEness MIP (AGREEMIP) metric tool.